نتایج جستجو برای: population growth

تعداد نتایج: 1459485  

Journal: :Ecology 2009
Jessica J Kuang Peter Chesson

We investigate the effect of seed predation on the coexistence of competing annual plants. We demonstrate a role for predation that is opposite to the conventional wisdom that predation promotes coexistence by reducing the intensity of competition. In the common situation where competitive coexistence involves intraspecific competition exceeding interspecific competition, predation can undermin...

2018
Hyeon-Ju Gim Chang-Hoi Ho Jinwon Kim Eun Ju Lee

Regional warming, owing to urbanization, leads to earlier spring phenological events and may expose plants to hard freeze damage. This study examined the influence of urbanization on the risk of frost damage to spring flowers in South Korea from 1973 to 2015. For the analysis period, we categorized 25 cities into two groups: those showing rapid population growth (rPG) ≥ 200,000, including 13 ci...

2011
Florian Altermatt Annette Bieger Francesco Carrara Andrea Rinaldo Marcel Holyoak

Metacommunity theory poses that the occurrence and abundance of species is a product of local factors, including disturbance, and regional factors, like dispersal among patches. While metacommunity ideas have been broadly tested there is relatively little work on metacommunities subject to disturbance. We focused on how localized disturbance and dispersal interact to determine species compositi...

2016
Sinéad Collins

I use an individual-based model to investigate the evolution of cell division rates in asexual populations under chronic environmental enrichment. I show that maintaining increased growth rates over hundreds of generations following environmental improvement can be limited by increases in cellular damage associated with more rapid reproduction. In the absence of further evolution to either incr...

2010
Boris A. Portnov

The Change of Support Problem (COSP) reflects a possibility that the outcome of an urban analysis may critically depend on the researcher’s choice of territorial units. To verify this assumption, the present study examines the association between population growth and population size of localities, using population growth data for two levels of geographic resolution 4,667 local administrative u...

2007
Pengyu Zhu Yaoqi Zhang

Extensive economic investigations have shown a variety of benefits derived from urban forests, but study on demand for urban forests remains limited. This study investigates the impact of selected potential factors on the demand for urban forests at the city level. An empirical economic model is used to examine and estimate the demand for urban forests in all cities with population over 100,000...

Journal: :Ecology 2014
Melissa L Aikens Deborah A Roach

Species' range limits can be caused by environmental gradients, and in such cases, abundance is thought to be highest in the center of a species range and decline towards the edge (the abundant-center model). Although in theory decreased abundance is caused by a decline in performance at the edge, it has been shown that performance and abundance are not necessarily related. Few studies have com...

2008
Michael Brady Brent Sohngen

This study takes advantages of recent developments in measuring total factor productivity in output specific directions to examine the influence of technological change in different agricultural sectors on land-use decisions in a cross-section of countries from 1969 to 2001. Results demonstrate a positive relationship between productivity and land in agriculture in most cases. The ruminant sect...

Journal: :The Journal of animal ecology 2011
Innes M W Sim Graham W Rebecca Sonja C Ludwig Murray C Grant Jane M Reid

1. Understanding how demographic variation translates into variation in population growth rate (λ) is central to understanding population dynamics. Such understanding ideally requires knowledge of the mean, variance and covariance among all demographic rates, allowing the potential and realized contribution of each rate to λ to be estimated. Such studies require integrated monitoring of all dem...

2012
Samuel K. Wasser Jessica I. Lundin

The report describes discrepancies between current and historical carrying capacity for the SRKW, but fails to discuss options for increasing current carrying capacity. The report also appears to be overwhelmingly focused on broad demographic associations between annual SRKW population growth and fish abundance that occur over a relatively long time scale. Too little attention is paid to change...

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